package com.java;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 多线程之间按顺序调用，实现A->B->C
 * 三个线程启动，要求如下:
 *
 * AA打印5次，BB打印10次，CC打印15次
 * 接着
 * AA打印5次，BB打印10次，CC打印15次
 * .....来10轮
 * 1.高内聚低耦合前提下，线程 操作 资源类
 * 2.判断/干活/通知
 * 3.多线程交互中，必须要防止多线程的虚假唤醒，也即（判断只用while，不能用if）
 * 4.标志位
 * @author jingjintao
 * @date 2021/10/23 - 22:51
 **/
public class ThreadOrderAccess {
    public static void main(String[] args) {
        ShareResource shareResource = new ShareResource();
        new Thread(() -> {
            for (int i = 1; i <= 10; i++) {
                shareResource.print5();
            }
        },"A").start();
        new Thread(() -> {
            for (int i = 1; i <= 10; i++) {
                shareResource.print10();
            }
        },"B").start();
        new Thread(() -> {
            for (int i = 1; i <= 10; i++) {
                shareResource.print15();
            }
        },"C").start();
    }
}

class ShareResource{

    private int number = 1;
    private Lock lock = new ReentrantLock();
    private Condition condition1 = lock.newCondition();
    private Condition condition2 = lock.newCondition();
    private Condition condition3 = lock.newCondition();

    public void print5(){
        lock.lock();
        try {
            //判断
           while (number != 1){
               condition1.await();
           }
           //干活
            for (int i = 1; i <=5 ; i++) {
                System.out.println(Thread.currentThread().getName()+"\t"+i);
            }
            number = 2;
           // 通知
            condition2.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }

    public void print10(){
        lock.lock();
        try {
            //判断
            while (number != 2){
                condition2.await();
            }
            //干活
            for (int i = 1; i <=10 ; i++) {
                System.out.println(Thread.currentThread().getName()+"\t"+i);
            }
            number = 3;
            // 通知
            condition3.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }

    public void print15(){
        lock.lock();
        try {
            //判断
            while (number != 3){
                condition3.await();
            }
            //干活
            for (int i = 1; i <=15 ; i++) {
                System.out.println(Thread.currentThread().getName()+"\t"+i);
            }
            number = 1;
            // 通知
            condition1.signal();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }

    }
}
